MftD Catalyzes the Formation of a Biologically Active Redox Center in the Biosynthesis of the Ribosomally Synthesized and Post-translationally Modified Redox Cofactor Mycofactocin
Year: 2019
Type: article
Abstract: Mycofactocin (MFT) is a putative ribosomally synthesized and post-translationally modified (RiPP) redox cofactor. The biosynthesis of MFT is encoded by the gene cluster mftABCDEF . While processing of the precursor peptide by MftB, MftC, and MftE has been shown to result in the formation of the small molecule 3-amino-5-[( p -hydroxyphenyl)methyl]-4,4-dimethyl-2-pyrrolidinone (AHDP), no activity has been shown for the putative dehydrogenase MftD and the putative glycosyltransferase MftF. In addition, evidence demonstrating that MFT is a redox cofactor has only been limited to the requirement of mft genes for ethanol assimilation in Mycobacterium smegmatis mc 2 155. Here, we demonstrate that MftD catalyzes the oxidative deamination of AHDP, forming an α-keto moiety on the resulting molecule, which we call pre-mycofactocin (PMFT). We characterize PMFT by 1D and 2D NMR spectroscopy techniques and by high-resolution mass spectrometry data to solve its structure. We further characterized PMFT by cyclic voltammetry and found its midpoint potential to be ∼255 mV. Lastly, we demonstrate that PMFT is a biologically active redox cofactor that oxidizes NADH bound by M. smegmatis carveol dehydrogenase ( Ms CDH) and can be used by Ms CDH in the oxidation of carveol. These data demonstrate for the first time that PMFT functions as a biologically active redox mediator and provides the most direct evidence to date that MFT is a RiPP-derived redox cofactor.
DOI: 10.1021/jacs.9b06102
Authors: Richard S. Ayikpoe, John A. Latham
Institution: University of Denver
Language: English
Subfield: Applied Microbiology and Biotechnology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2965649016